Search

Higenamine (HG), is one of the main active components in many widely used Chinese herbs, and a common ingredient of health products in Europe and North America. Several groups, including our own, have previously shown the beneficial effects of HG against cardiomyocyte death during acute ischemic damage. However, the effect of HG on chronic cardiac remodeling, such as cardiac fibrosis, remains unknown. Herein, we aim to investigate the role of HG in cardiac fibrosis in vivo as well as its cellular and molecular mechanisms. Chronic pressure overload with transverse aortic constriction (TAC) significantly increased cardiac hypertrophy, fibrosis, and cardiac dysfunction in mice, which were significantly attenuated by HG. Consistently, cardiac fibrosis induced by the chronic infusion of isoproterenol (ISO), was also significantly reduced by HG. Interestingly, our results showed that HG had no effect on adult mouse CM hypertrophy in vitro. However, HG suppressed the activation of cardiac fibroblasts (CFs) in vitro. Furthermore, TGF-β1-induced expression of ACTA2, a marker of fibroblast activation, was significantly suppressed by HG. Concomitantly, HG inhibited TGF-β1-induced phosphorylation of Smad2/3 in CFs. HG also reduced the expression of extracellular matrix molecules such as collagen I and collagen III. To our surprise, the inhibitory effect of HG on CFs activation was independent of the activation of the beta2 adrenergic receptor (β2-AR) that is known to mediate the effect of HG on antagonizing CMs apoptosis. Our findings suggest that HG ameliorates pathological cardiac fibrosis and dysfunction at least partially by suppressing TGF-β1/Smad signaling and CFs activation. • Higenamine ameliorates cardiac remodeling and/or dysfunction in a variety of mouse models. • Higenamine attenuates cardiac fibrosis. • Higenamine suppresses cardiac fibroblast activation and matrix protein expression. • This effect is dependent on TGF-β1/Smad signaling but not β2-adrenergic receptor, a previously known target of Higenamine. [ABSTRACT FROM AUTHOR]